Part 4 of 4

Fig. 21 Wiper Module:

WIPER MODULE
The wiper motor bracket is secured with two screws below the wiper motor through two rubber insulators to the bottom of the cowl plenum panel beneath the cowl plenum cover/grille panel. Two screws secure the top of the wiper module bracket to the cowl plenum panel through rubber insulators located on the outboard end of each pivot bracket. The ends of the wiper pivot shafts that protrude through dedicated openings in the cowl plenum cover/grille panel to drive the wiper arms and blades are the only visible components of the wiper module.

The wiper module consists of the following major components:
- Bracket - The wiper module bracket consists of a long tubular steel main member that has a die cast pivot bracket formation near each end where the two wiper pivots are secured. A stamped steel clamp secures the center of the tubular member to the die cast bracket integral to the wiper motor with two screws.

- Crank Arm - The wiper motor crank arm is a stamped steel unit with a slotted hole on the driven end that is secured to the wiper motor output shaft with a nut, and has a ball stud secured to the drive end.

- Linkage - Two stamped steel drive links connect the wiper motor crank arm to the wiper pivot lever arms. The left side drive link has a plastic socket-type bushing on each end. The right side drive link has a plastic socket-type bushing on one end, and a plastic sleeve-type bushing on the other end. The socket-type bushing on one end of each drive link is snap-fit over the ball stud on the lever arm of its respective pivot. The right side drive link sleeve- type bushing end is then fit over the motor crank arm ball stud, and the other socket-type bushing of the left side drive link is snap-fit over the exposed end of the wiper motor crank arm ball stud.

- Motor - The wiper motor features an integral die cast bracket to which the wiper module bracket is secured with a stamped steel clamp and two screws near the top and which has two rubber insulated mounting ears at the bottom. This die casting also serves as the wiper motor transmission housing from which the wiper motor output shaft exits. A nut secures the wiper motor crank arm to the motor output shaft. The two-speed permanent magnet wiper motor features an integral transmission, an internal park switch, and an internal automatic resetting circuit breaker.

- Pivots - The two front wiper pivots are secured within the die cast pivot brackets on the outboard ends of the wiper module main member. The lever arms that extend from the center of the pivot shafts each have a ball stud on their end. The upper end of each pivot shaft where the wiper arms will be fastened each has a serrated driver with a keyway. The lower ends of the pivot shafts are installed through lubricated bushings in the pivot brackets and are secured with snap rings.

The wiper module cannot be adjusted or repaired. If any component of the module is faulty or damaged, the entire wiper module unit must be replaced.

The wiper module operation is controlled by the battery current inputs received by the wiper motor through the wiper ON/OFF and wiper high/low relays. The wiper motor speed is controlled by current flow to either the low speed or the high speed set of brushes. The park switch is a single pole, single throw, momentary switch within the wiper motor that is mechanically actuated by the wiper motor transmission components. The park switch alternately opens and closes the wiper park switch sense circuit to ground, depending upon the position of the wipers on the glass. This feature allows the motor to complete its current wipe cycle after the wiper system has been turned Off, and to park the wiper blades in the lowest portion of the wipe pattern. The automatic resetting circuit breaker protects the motor from overloads. The wiper motor crank arm, the two wiper linkage members, and the two wiper pivots mechanically convert the rotary output of the wiper motor to the back and forth wiping motion of the wiper arms and blades on the glass.

Fig. 23 ISO Micro Relay:

WIPER ON/OFF RELAY
The wiper ON/OFF relay is located in the Integrated Power Module (IPM) in the engine compartment near the battery The wiper ON/OFF relay is a conventional International Standards Organization (ISO) micro relay. Relays conforming to the ISO specifications have common physical dimensions, current capacities, terminal patterns, and terminal functions. The relay is contained within a small, rectangular, molded plastic housing and is connected to all of the required inputs and outputs by five integral male spade-type terminals that extend from the bottom of the relay base.

The wiper ON/OFF relay cannot be adjusted or repaired and, if faulty or damaged, the unit must be replaced.

The wiper ON/OFF relay is an electromechanical switch that uses a low current input from the Front Control Module (FCM) to control a high current output to the wiper motor. The movable common feed contact point is held against the fixed normally closed contact point by spring pressure. When the relay coil is energized, an electromagnetic field is produced by the coil windings. This electromagnetic field draws the movable relay contact point away from the fixed normally closed contact point, and holds it against the fixed normally open contact point. When the relay coil is de-energized, spring pressure returns the movable contact point back against the fixed normally closed contact point. A resistor is connected in parallel with the relay coil in the relay, and helps to dissipate voltage spikes and electromagnetic interference that can be generated as the electromagnetic field of the relay coil collapses.

The wiper ON/OFF relay terminals are connected to the vehicle electrical system through a connector receptacle in the Integrated Power Module (IPM). The inputs and outputs of the wiper ON/OFF relay include:
- Common Feed Terminal - The common feed terminal (30) is connected to the common feed terminal of the wiper high/low relay at all times through the wiper ON/OFF relay output circuit.

- Coil Ground Terminal - The coil ground terminal (85) is connected to a control output of the Front Control Module (FCM) through a wiper ON/OFF relay control circuit. The FCM controls wiper motor operation by controlling a ground path through this circuit.

- Coil Battery Terminal - The coil battery terminal (86) receives battery current at all times from a fuse in the IPM through a fused ignition switch output (run-acc) circuit.

- Normally Open Terminal - The normally open terminal (87) receives battery current at all times from a fuse in the IPM through a fused ignition switch output (run-acc) circuit, and provides battery current to the wiper ON/OFF relay output circuit whenever the relay is energized.

- Normally Closed Terminal - The normally closed terminal (87A) is connected to ground at all times through a take out of the left headlamp and dash wire harness with an eyelet terminal connector that is secured by a screw to the front end sheet metal, and is connected to the wiper ON/OFF relay out- put circuit whenever the relay is de-energized.

The wiper ON/OFF relay can be diagnosed using conventional diagnostic tools and methods. However, conventional diagnostic methods may not prove conclusive in the diagnosis of the instrument cluster, the Front Control Module (FCM), or the electronic message inputs to or outputs from the instrument cluster and the FCM that control the operation of the wiper ON/OFF relay. The most reliable, efficient, and accurate means to diagnose the wiper ON/OFF relay, the instrument cluster, the FCM, or the electronic message inputs and outputs related to the wiper ON/OFF relay operation requires the use of a DRB III scan tool. Refer to the appropriate diagnostic information.